R.E.D

If you do end up removing the eup, install new bolts and o rings ..the bolts tend to break.. specially if never been changed.As  mentioned above , pull the eup roller and check the protrusion of the roller guide pin... attached is an image of the roller  pin almost flush with the eup housing wall,it made the roller spin and trashed the cam .. this is my on my cousin's truck , it had a miss and blink  code for the eup. Hopefully yours is not that bad. Just my two cents

RED

While you have the plugs off, check for signs of coolant or oil seepage. The coolant or oil sensors go bad and allow the wiring lining to be used as a hose. The coolant especially will react with the electricity and create kind of a electrolysis and corrode your male connector pins. Had this happened to me once.

Nice looking rig👍

On 11/5/2022 at 11:27 PM, R.E.D said:

Selling my quint axle dump truck.ami 370 hp , t310m transmission,4.42gear ration on 44k camelback.19.5 foot bed with 60 inch sides.870,000 miles and counting.truck has 3 steerable drop axles ,dump body vibrator.Works every day .located in Houston area .60k$ asking price,open to all offers.

Sold 

Selling my quint axle dump truck.ami 370 hp , t310m transmission,4.42gear ration on 44k camelback.19.5 foot bed with 60 inch sides.870,000 miles and counting.truck has 3 steerable drop axles ,dump body vibrator.Works every day .located in Houston area .60k$ asking price,open to all offers.

Well this happened to me once , I was working on the truck and removed the air cleaner canister.after putting it back, engine would stutter and stumble..ended up being the air canister cone mount that's supposed to seal against the hood and drag in cool air from outside..it must have moved in the process and truck was sucking in all the hot air from the engine bay..

1 hour ago, DieselDog5.9 said:

I have seen this setup in single axle plow trucks, the little peanuts come out and lock against the outer plate, but I did not think it was selectable, thought it acted as a locker/posi works in a car differential.

Any Mack I have seen with "quad locks" has hendrickson suspension and Rockwell or Eaton rears.

Yeah..it engages and disengages at will..Great design 

I'm not sure that mack rear ends had "full lockers".they did have interwheel locking differentials which I believe uses cams just like the interaxle power divider.But I think they are pretty rare and parts would be hard to source..

Mine is governed at 70mph.. grossing 72k in a quint axle dump , I don't feel like I need to or want to go any faster..

Red

These engines have a scavenge bump of the camshaft lobe..which makes them intake some exhaust gas with the fresh pressurized air..it makes the oil very dirty and easily full of sludge.I find that every time my engine is getting close to the oil change, the egts also Begin to climb.

I have the same same gear ratio as you and same tire size.its great off road..but I have a mack trans with a bit more overdrive.

At 1800 rpm you will be at 69mph

What tires are on the truck?

https://wellertruck.com/road-speed-calculator

This is a road speed calculator.Input your info to find out speed.Your eaton trans if it is over drive has a overdrive of 0.73. I believe 

https://www.bigmacktrucks.com/topic/50251-mack-ai460-ai427-ami-low-torque-low-horsepower-poor-fuel-mileage-granite-dead-dog-remediation/?do=findComment&comment=372944

UPDATE:A month ago  I removed the rocker arm assembly from the back head.Replaced Rocker bolts with new ones and torqued to spec.. adjusted the valves on 4,5,6 and the ticking went away...I'm baffled..I wanted to run the truck for at least a month before I reported back to you guys..old rocker bolts were tight.Rocker arm base was seemed ok and not wearing into the head..the actual rocker arms had no play on the shaft.I did compress the spring on the #4 pushrod by hand and it also seemed ok.what you guys think?

Red

I just changed mine Sunday.  same thing happened to me.

Wouldn't hurt to check fuel pressure at the galley plug at the front of engine by Crank case filter.

33 minutes ago, Mark T said:

Come on......lets be fair here. I can remember as long back as I can remember (which is before I even knew what the stuff was) At first ?   "those transmissions with the bronze in them were never gonna last"  then "there's more and more fiberglass"  then "I'm not driving anything my foot doesn't go straight to a injection pump" .  Old trucks are cool..... but let's see anyone who's driven a new one do 4 or 5 hundred miles a day in an R Model with a 300 and a five speed after having driven  an  Anthem with a 505 and M Drive  .  Always been just work horse trucks. How many White 9000s you see restored ?  Truth is we all love the trucks from our own era. That being said...... yeah, if there's a new Mack ???  It's game over for everything but the name. Volvo did it to White, GMC , even the mighty Autocar.   Personally, I can't believe it's taken them so long to deep 6 the Macks.

That's also true.Yet what I think everyone is trying to convey is  that they could've made a new comfortable truck that was also long lasting.I bet when the R model cabs came out in the 60s those guys riding B models were able to enjoy a nicer yet long lasting vehicle..R model cab was in production like 40 years , someone correct me if I'm wrong.

21 hours ago, Bullheaded said:

As far as new trucks go, yes they look okay. But they are not a REAL Western Star. It's a higher priced Freightliner. Gone is the steel cab, nice interior, nice gauges, and I'll probably be safe to bet they are now multi-plexed with modules. Not the same tough Western Star frame either.

I have a friend that bought one new and had an accident that damaged one side of the cab. His brand new truck was down a YEAR waiting for parts that STAR nor Freightliner had or would give up from the factory. Apparently the doors are Freightliner Columbia doors. And that was one of the things they had no new ones in stock.

Well, that's what trucks are now, junk meant to be traded in after 500k miles or 5 years..they are not going to build a truck that last 20 years because they would go broke.that applies to everything nowadays..must be why freight shakers dominate market share..they went with cheap and easily braekable. 

Incredible!Those guys at the dealership will try to sell you tire patches for train wheels..